This invention relates to display arrangements for motor vehicle mirrors.
In the field of automotive technology problems arise first because an ever-increasing quantity of data is provided to a vehicle operator while moving in road traffic, and second because the existing data display space is limited. Moreover, a large number of independent display devices leads to a certain lack of recognition by the operator, rendering timely perception of the information displayed more difficult.
German Offenlegungsschrift No. 37 20 848 discloses a display arrangement for motor vehicles which is incorporated in a structural unit with the rear view mirror of the vehicle. In order to provide the minimum possible interference with the operator's rearward vision in the rear view mirror, an LCD is arranged behind an area of the reflecting surface of the mirror which is partly transmissive to light. The LCD, which is lighted from the rear, is electronically controlled to display data in such manner that the light is visible to the operator through the LCD in the activated and/or unactivated areas and through the partially light-transmissive mirror surface. In order not to restrict the operator's field of vision, an enlarged mirror surface is provided. However, this leads to an enlargement of the overall dimensions of the mirror unit. Another disadvantage is that the dimensions of the LCD and of the associated electronic circuits are very bulky, further increasing the overall dimensions of the rear view mirror unit. Furthermore, such LCDs are very expensive.
German Offenlegungsschrift No. 37 35 847 discloses a rear view mirror having an LCD display surface located in the mirror housing immediately below the mirror surface. However, a disadvantage of this arrangement is that the display area is not located directly within the operator's usual field of view. In order to read the data, therefore, the driver must shift his view downwardly from the mirror.
There are also conventional motor vehicle rear view mirrors having a glass mirror with a phototechnically controlled antiglare layer including a photoelectric transducer connected to an electric circuit arranged on a board. One such rear view mirror is disclosed for example in European Published Application No. 78 51 03 in which a light conductor has a free end face adjacent to the mirror glass and substantially parallel to its outer surface with the other end face is adjacent to a photoelectric transducer mounted on a board.
German Patent No. 197 02 746 discloses an outside rear view mirror having a repeat blinker provided in the mirror housing. To replace conventional incandescent lamps, which generate much heat and are very bulky as well, this reference discloses mounting an LED as a light source in the mirror housing and connecting it by a light guide to a light exit aperture in the mirror housing.